The objective of this project is to clarify the mechanism(s) by which human immunity to Bordetella pertussis infection is mediated. Pertussis is a serious respiratory infection in infants and children. Control depends upon a thimerosal-treated, whole organism vaccine which is associated with adverse reactions and provides short-lived immunity. Progress in understanding the pathogenesis of this infection and its immunity has been slow because of the lack of an experimental model clearly applicable to humans. The specific aims of this project are to determine if B. pertussis organisms adhere selectively to ciliated cells of the human respiratory tract and to investigate the effect on adherence of serum, saliva, and nasal secretions from individuals with natural and vaccine-induced immunity. Interaction of organisms and suspensions of squamous and collagenase-dispersed ciliated tracheal mucosal cells will be studied to determine whether there is selective attachment to cilia. Adherence will be assayed by light and fluorescence microscopy. Exposure of organisms to fragments of human nasal polyp in organ culture will also allow determination of specific attachment to cilia. With the polyp fragments maintained in organ culture, the effect of infection on ciliary activity will be determined by direct observation. Serum, saliva, and nasal secretions will be obtained from children before and after pertussis immunizapion and from patients convalescent from clinical pertussis. The effect of these sera and secretions on attachment of organisms to human respiratory epithelial cells will be studied. Ultimately, this basic information may permit the rational design of a safer vaccine directed at the components of the organism important in clinical disease.